Lewis Hamilton has set the early pace in the opening practice session for this weekend’s Spanish Formula 1 Grand Prix.

The Mercedes driver, who is gunning for four wins on the trot, was comfortably the fastest driver at the end of the opening 90-minute session, lapping almost a second faster than McLaren’s Jenson Button and Red Bull Racing’s Daniel Ricciardo. Crowd favourite Fernando Alonso was fourth-fastest in the Ferrari.

Ominously, Hamilton and teammate Nico Rosberg set the early pace as practice got underway in beautiful conditions at Barcelona’s Circuit de Catalunya.

Vettel stopped on track with an electrical failure.

But all did not go perfectly to plan for the Silver Arrows, with Rosberg being restricted to just nine laps in the session after his F1W05 was hit with a suspected Energy Recovery Store cooling issue in his Mercedes power unit.

That allowed Button, Ricciardo and Alonso to leapfrog ahead of him in the final reckoning, although Rosberg managed more running than his compatriot and reigning champion Sebastian Vettel. His Red Bull ground to halt after just four tours with an electrical problem, which caused enough damage to a wiring loom that will ensure he won’t take to the track in the afternoon’s second practice session.

Kimi Räikkönen managed the sixth-fastest time in the second Ferrari, with Kevin Magnussen, Pastor Maldonado, Sergio Pérez and Felipe Massa rounding out the top ten.

The session featured a couple of strange incidents. Pérez suffered an unusual failure of his left-hand mirror mount, while Sauber reserve driver Giedo van der Garde was lucky to avoid an accident after his heavily revised C33 suffered an apparent brake failure at Turn 1.

Friday’s second free practice session in Barcelona gets underway at 2:00pm local time (GMT +2).